Apparatus for heat treatment of textured yarn warp sheets and method



Aprll 1965 D. E. FISHER ETAL 3,180,004

APPARATUS FOR HEAT TREATMENT OF TEXTURED YARN WARP SHEETS AND METHOD Filed July 19, 1963 INVENTORS DON E. FISHER WILLIAM H. HILLS DAVID M. MULLINS ATTOR Y United States Patent 3 lStMlild APPARATUS FUR HEAT TREATMENT OF TEX- TURED YARN WARP SI-FEETS AND METHQD Don E. Fisher, William H. Hills, and David Martin Mullins, Pensacola, Fla, assignors to Monsanto Company, a corporation of Deiaware Filed July 19, 1963, Ser. No. 296,172 6 Claims. (Cl. Ed -59) The present invention relates to a method and apparatus for heat treatment of textured yarn warp sheets under conditions permitting retention of the maximum degree of bulking. In one aspect of the invention, the treated yarn is recovered in the form of a warp sheet.

Several end uses require heat or steam treatment of yarn. As an example, many carpet constructions require intermittently dyed yarn. After dye has been applied to the yarn by the well known Vigoreaux printing system, an engraved roll fabric printing machine, or other suitable means, the dye must normally be fixed or caused to migrate into the interior of the yarn filaments. A very effective fixation method commonly employed is the steaming of the yarn at atmospheric pressure for about minutes (in the case of nylon), or at higher pressures in which case less time is required. After steaming, the yarn is com monly washed to remove any surplus dyestuif as well as thickening agents and other components employed in the dye paste. The yarn is next dried and wound up, each threadline on its own package.

To effect uniformity in dye application and to reduce the cost of the dyeing operation it is desirable to perform the dyeing, steaming, washing, drying and winding steps in one continuous operation. This continuous operation makes it difficult to carry out the dye fixation step when continuous filament thermally set textured yarns are being treated, since such yarns generally tend to lose their bulkiness when subjected to even low tension at elevated temperatures. The amount of bull; loss for each temperature and tension combination varies somewhat from one yarn to another depending on the method of texturing used. However, it is generally desirable to carry out the steam dye fixation step at the lowest possible tension thereby retaining the maximum possible bulkiness.

According to the prior art, such dye setting involves passing a warp sheet of yarn in a zig-zag path, over a series of driven rolls, through a steam chamber. This arrange- .ent maintains separation of the several threadlines in the warp sheet but generally requires that the yarn in the steam chamber be maintained at a tension which severely impairs the bulking capabilities of the yarn. For example a particular commercially available textured yarn, prepared in accordance with the teachings of Bromley et 21. US Patent No. 3,024,516 may have a bulking value of approximately 16 percent before intermittent dyeing. After intermittent dyeing by most commercial techniques this particular yarn will have a bulk value or" between 5 and 10 percent. Yarn treated according to the present invention will have a bulk value of about -16 percent. To determine bulk value, a meter skein of yarn is wound on a 1% meter circumference reel and the ends tied. The skein is steamed under no tension in 5 pounds per square inch (p.s.i.) saturated steam for 5 minutes. The skein is then removed from the steam, allowed to cool and measured as follows. A 3.1x l0 grams per denier Weight is hung on the skein for seconds, to obtain a length B. An 0.028 gram per denier weight is then hung on the skein for 20 seconds, to derive a length A. Bulk value is defined as The B measurement should always be made first, then the A measurement.

Accordingly, a primary object of this invention is to provide a method for economically heat treating textured yarns.

A further object is to provide a method of the above character which permits retention of a maximum amount of bulk value.

A further object is to provide a method of the above character wherein the yarn is treated in the form of a warp sheet and recovered in the form of a warp sheet.

A further object is to provide a method of the above character particularly adapted for economical setting of dyes while retaining maximum yarn bulk value.

A further object is to provide apparatus for performing the above methods.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the apparatus embodying features of construction, combinations of elements and arrangement of parts which are adapted to effect such steps, all as exemplified in the following detailed disclosure, and the scope of the invention Will be indicated in the claims.

For a more complete understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in connection with the accompanying drawing, in which:

FIGURE 1 is a schematic perspective view of a first embodiment of the invention, and

FIGURE 2 is a schematic side elevation view of a second embodiment of the invention.

Referring generally to FIGURE 1, the above objects are achieved by the illustrated apparatus wherein a Warp sheet 249 of textured yarns is passed by a suitable feed mechanism 22 into the long upper or inlet leg 24 of a. heat treating chamber 26 in the form of a J-box. After the yarns have progressed through the J-box, they are removed from the short lower or exit leg 28 thereof in the form of a tow 3d, and are then separated and reformed into a warp sheet 32 by warp-forming apparatus indicated generally at 34. The recovered warp sheet may be further processed, if desired, by further steps such as washing, drying and rewinding.

Referring now more specifically to FIGURE 1, warp sheet 29 may be supplied from any conventional source. The term warp sheet, as used herein, refers to a plurality of parallel threadlines or yarns arranged in the form of a sheet. As an example, such a warp sheet may be supplied from a conventional engraved roll fabric printing machine, Vigoreaux printer, or other suitable means which applies a dye paste to the warp sheet.

Feed mechanism 22 includes a group of feed rolls 36 and a plaiting mechanism 40. The feed rolls preferably do not have smooth finishes; advantageously they may have corrugated or discontinuous surfaces, thus substantially reducing smearing of the dye and reducing the tendency of the warp sheet to adhere to the rolls. Rolls made of parallel rods arranged in a cylindrical configuration are illustrated, and have been found to be particularly satisfactory. It has been found to be desirable for each downstream roll to have a slightly higher peripheral velocity (on the order of 1-5 percent) than the preceding roll to prevent loss of tension between the rolls.

The heating chamber 26 provides for heat treating the warp sheet 20 for the required time interval undersubstantially no tension to prevent destruction of the bulk which is simultaneously developed with the setting of the dye. Heating chamber 26 comprises walls defining a rectangular passage extending vertically downwardly from the open upper end of inlet leg 24 over the major portion of its length, after which the passage curves gradually upwardly to terminate in an upwardly directed exit leg 28. The interior of the passage is preferably smooth in order to facilitate passage of the yarn downwardly, and advantageously the cross section may increase gradually along the length of the passage proceeding toward exit leg 28.

The dimensions and proportions of the heating chamber are important in securing proper movement of the yarn during the heating treatment. The yarn is piled in the heating chamber 26 through the open end of inlet leg 24- until the heating chamber is nearly full. The mass of yarn slowly moves through the chamber under the infiuence of gravity until it is removed upwardly from exit leg 28. This movement of the yarn is controlled by friction between the walls of the box and the yarn mass. The friction may be selected or controlled by proportioning the box cross-sectional dimensions so as to provide a proper passage-wall peripheral area contacting a given volume of yarn.

As a specific example, a suitable aluminum heating chamber for treating twenty-four threadlines of 3690 denier textured continuous filament nylon had a height of about ten feet at leg 24 and a height of about two feet at leg 28. The passage had cross-sectional dimensions of 3" x which provides an area to volume ratio of 0.94. This ratio should be greater than 0.5 unless the passage is lined with a low friction material such as polytetrafiuoroetnylene. An alternative to a low friction lining material would be to increase the cross-sectional area of the passage as the yarn progresses toward exit leg 28.

For best results in yarn removal and retention of the maximum degree of bulk, the area to volume ratio, box height, and the wall coefiicient of friction should be adjusted so that the yarn mass makes a full 180 turn in the bottom of the passage and then travels straight up before the strands are picked up from their packed condition.

Warp sheet 29 preferably is supplied by the feed rolls through a plaiting mechanism 4% to the inlet leg 24 of the heating chamber 26. The plaiter 40 comprises a guide chute or tube arranged below the output drive roll 38 and directly above the inlet leg 24 of heating chamber The lower end of plaiter at is oscillated back and forth normal to the plane of warp sheet 20 so that the yarn is continuously laid in heating chamber 26 in superimposed loose folds (plaits). This plaiting step greatly reduces the tendency of the several individual yarns or threadlines to snarl and tangle during the heat treating operation. Plaiting equipment is well known in the textile arts; such equipment is available from the Rodney Hunt Company, for example.

In the specifically disclosed context of dye setting, it is desirable to treat the yarn with saturated steam under from ()5 pounds per square inch. A steam manifold 42 is illustrated as mounted on the side of heating chamber 26. A steam supply line 44 supplies the necessary steam from a convenient source to manifold 42, and a plurality of individual steam distribution lines 46 distribute the steam from manifold 42 to spaced points along the passage. The treating steam should be supplied in such a fashion that the yarn is not subjected to high velocity jets of steam, in order to retain maximum bulking and minimum tanglin g. In a preferred embodiment, the steam distribution lines 4-6 communicate with the interior of the passage by a series of relatively large apertures in the passage walls, for example, apertures. Alternatively, this may be accomplished by suitably bafiling the steam inlets into the passage, or by supplying the steam under sufficiently low pressure. The walls of the heating chamber 26 should be jacketed or otherwise heated by some conventional means to about 105 C. in order to prevent or reduce condensation of the steam. A drain passage 48 may be provided in the bottom of the J-box in order to remove condensate.

The several yarns withdrawn from exit leg 28 will be in a tangled condition, resembling a tow, instead of in the form of a warp sheet. The individual yarns must be separated and rearranged into a Warp sheet for further processing, such as washing, drying, etc. The angled tow it) cannot be directly combed into a warp sheet in a single combing operation. However, this may be accomplished efficiently by dividing the tow in at least two stages, with shaking of the yarns before each division. Thus, the tow may be first divided into groups having several thrcadiines per group, and then further subdivided into individual threadlines. Two embodiments of this concept are herein disclosed.

A first exemplary warp-forming apparatus 34 for reforming the tangled tow 39 withdrawn from exit leg 23 illustrated in FIGURE 1. As shown therein, the yarn is withdrawn upwardly by a pair of driven nip rolls 50. The yarn next is fed down under an idler roll 52, up over a further idler roll 54, and finally through a second pair of nip rolls 55. A first group comb 56 is positioned just above idler roll 52, and separates tow 3% into groups, each of which includes several threadlines. It has been found that the separation into groups containing a small number of threadlines is greatly facilitated by provision of tow shaking apparatus in two locations before the tow arrives at comb 56. Thus a first shaker 58 may be positioned between nip rolls 5d and exit leg 28, to shake or oscillate the rising tow St? at its natural frequency, which may be of the order of 1 cycle per second. The second shaker 6t} may be positioned between nip rolls 5%) and group comb 55, and advantageously may oscillate at a somewhat higher frequency than shaker 53. Each shaker may include a pair of horizontal guide bars, reciprocated by conventional means in the directions shown by the arrows.

Preferably the groups of threadlines provided by group comb 56 are laterally separated a distance of several inches as they leave comb 56. The several groups are then passed under idler roll 52 and through a final shaker 62 before reaching the end comb 64. Shaker 62 preferably is oscillated at a still higher frequency than either of shakers 553 and 6%, for example at 60 cycles per second. End comb 64- has enough teeth to separate the individual threadlines from one another, so that the tangled tow 30 issuing from exit leg 28 of the heating chamber 26 leaves end comb 64- in the form of a reconstituted warp sheet 32.

Preferably, the nip rolls 5% are located at least 6 feet above exit leg 2%, and the tow travels at least 10 feet from nip rolls 55) to comb 5% at 25 yarns per minute, and farther at higher speeds. In the warp sheet of twenty-four threadlincs noted above, comb 56 may divide the tow into two or three groups having equal numbers of threadlines, and end comb 64 will subdivide each of these groups to recover the twenty-four individual threadlines in the form of warp sheet 32. Since the yarn is not subjected to steam and heat after leaving leg 28, tension may be applied to it without reducing its bulk. Thus the relative speeds of nip rolls 5th and 55 may be adjusted to provide sufiicient tension for efficient separation of the threadlines.

Referring now to FIGURE 2, an alternative warpformins apparatus 34 is illustrated. As shown therein, the tangled yarn 3Q issuing from exit leg 28 of heating chamber 26 is passed upwardly over an idler roll 66, then repeatedly down and up over a series of idler rolls 68 and 7t as many times as necessary to separate the ends. The FIGURE 2 embodiment includes shakers 53, 6t) and 62 as in FIGURE 1, but further includes an additional group comb '74 positioned before the yarn 39 reaches the first idler roll 66. With this arrangement, the yarn 3t withdrawn from exit leg 28 will leave the box in at least partially separated form as illustrated. As an example, the first group comb '74 in FIGURE 2 may separate the tow into a relatively small number of bundles, each bundle containing a large number of individual filaments. The second group comb '76 then separates these bundles into smaller bundles containing a lesser number of individual threadlines per bundle, while the final separation into individual threadlines is performed by end comb 64. As in the FIGURE 1 embodiment discussed above, the frequency of shaking should increase as the bundles are further subdivided.

it should be understood that with either of the disclosed embodiments more stages of division may be provided if necessary, particularly when a larger number of threadlines is being processed.

Since it is generally not feasible to attain proper control of the level of the yarn in treating chamber 26 by simply synchronizing the speeds of feed rolls 36 and the nip rolls at the output side of the heating chamber 26, preferably some sort of level sensing device is provided for detecting the level of yarn in the inlet leg 24, such as the photocell illustrated at 78 in FIGURE 1. Other equivalent level sensing devices are known to those skilled in the art and may be used instead of a photocell. The output of the level sensing device may be used to vary the speed of the feed rolls 36 so as to maintain the proper level of yarn in heating chamber 26.

For reliable threadline separation, it is highly desirable that the warp sheet 2t and the reconstituted or reformed warp sheet 32 have the threadlines arranged in the same order from edge to edge. This may be accomplished by leasing warp sheet 2% before it is fed through heating chamber 26, and passing this lease through the heating chamber and through the warp-forming apparatus 34. Care should be taken that the lease is not allowed to twist as it goes through the heating chamber.

From the above description and the accompanying drawing there has been disclosed an efficient process for economically heat treating textured yarns under conditions which permit retention of a maximum amount of bulk value. The yarn is subjected to heat only while under essentially no tension. The heat treatment causes some degree of tangling of the yarns; accordingly the disclosed method of dividing the treated yarn in at least two stages permits efficient reseparation of the tangled mass of yarn so that the yarn may be recovered in the form of a warp sheet. The above method has been disclosed as accomplished by specific apparatus, but the method is not so limited.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are etficiently attained and, since certain changes may be made in carrying out the above method and in the constructions set forth without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A process for steam-treating a warp sheet of threadlines having latent crimps comprising in combination:

(a) plaiting said warp sheet into the upper end of a heated J-box,

(b) steaming said plaited threadlines,

(c) removing said threadlines from the lower end of said J-box in the form of a tow, d) and reconstlucting said warp sheet by the following steps:

(1) lifting said tow from the lower end of said J-box, (2) shaking said tow before dividing, (3) dividing said tow into a plurality of groups,

each group containing several threadlines, (4) shaking said groups, (5) and subdividing said groups into individual threadlines. 2. A process for steam-treating a warp sheet of threadlines having latent crimps comprising in combination:

(a) plaiting said warp sheet into the upper end of a heated J-box, (b) steaming said plaited threadlines, (c) removing said threadlines from the lower end of said J-box in the fonn of a tow, (d) and reconstructing said warp sheet by the following steps:

(1) lifting the free ends of said threadlines in the form of a tow from the lower end of said J-box, (2) repeatedly dividing said tow a plurality of times until the individual threadlines are separated from one another, (3) and shaking said tow before dividing and between consecutive dividing steps. 3. Yarn treating apparatus comprising in combination: (a) walls defining a generally J-shaped treating passage having an upper inlet leg and a lower exit leg, (b) steam supply lines supplying steam to a plurality of points on the upper inlet leg, (c) feed means feeding yarn into the upper end of said inlet leg, (at) and means for recovering said yarn from said exit leg comprising:

(1) means for withdrawing said yarn from said exit leg in the form of a tow,

(2) first shaker means for oscillating said tow,

(3) group comb means for forming said tow into a plurality of groups of threadlines,

(4) second shaker means for shaking said groups of threadlines,

(5) and end comb means for separating the individual threadlines from one another to form a warp sheet.

4. The combination defined in claim 3 wherein said feed means feeds said yarn in the form of a warp sheet into said inlet leg.

5. The combination defined in claim 3 wherein said feed means includes a plaiting mechanism.

6. The yam treating apparatus defined in claim 3, further com-prising yarn level sensing means disposed near the upper end of said inlet leg, and speed control means responsive to said level sensing means for so controlling said feed means as to maintain the level of yarn substantially constant in said treating passage.

DONALD W. PARKER, Primary Examiner. 

3. YARN TREATING APPARATUS COMPRISING IN COMBINATION: (A) WALLS DEFINING A GENERALLY J-SHAPED TREATING PASSAGE HAVING AN UPPER INLET LEG AND A LOWER EXIT LEG, (B) STEAM SUPPLY LINES SUPPLYING STEAM TO A PLURALITY OF POINTS ON THE UPPER INLET LEG, (C) FEED MEANS FEEDING YARN INTO THE UPPER END OF SAID INLET LEG, (D) AND MEANS FOR RECOVERING SAID YANR FROM SAID EXIT LEG COMPRISING: (1) MEANS FOR WITHDRAWING SAID YARN FROM SAID EXIT LEG IN THE FORM OF A TOW, (2) FIRST SHAKER MEANS FOR OSCILLATING SAID TOW, (3) GROUP COMB MEANS FOR FORMING SAID TOW INTO A PLURALITY OF GROUPS OF THREADLINES, (4) SECOND SHAKER MEANS FOR SHAKING SAID GROUPS OF THREADLINES, (5) AND END COMB MEANS FOR SEPARATING THE INDIVIDUAL THREADLINES FROM ONE ANOTHER TO FORM A WARP SHEET. 